Process for improving the magnetic qualities of a magnetic body.



No Drawing. Application filed March 2 1, 1907, Serial No. 363,657. Renewed 'May 26, 1914. Serial No.

7 heat the body to a relatively high tempera- 'n'nrTnn sTaTns FATENT ornion.

ROBERT ABBOTT HADFIELD, OF SHEFFIELD, ENGLAND.

PROCESS FOR IMPROVING THE MAGNETIC QUALITIES DEA-MAGNETIC BODY.

Specification of Letters Patent.

Patented Dec. 4.

To all whom 'itmay concern .1

Be it known that I, ROBERT ABBOTT HAD- FIELD, a subject of the King of Great Britain, of Sheffield, England, have invented. a certain new and useful Improvement in Proc' esses for Improving the Magnetic Qualities of a Magnetic Body, of which the following is a specification.

The invention is a process for improving certain magnetic qualities of a magnetic body, and more especially of alloys of iron and silicon, or iron-silicon and aluminium, or iron-silicon and manganese,'in order to increase the magnetic permeability and electric resistance and lower the hysteresis action of the said body; and thus to adapt it for use in ballast-coils, transformer-plates and like electrical apparatus, where the reduction of magnetic and electric losses to the lowest possible degree is of great importance.

In carrying my process into. effect, I first ture below its melting point and say between 900 and 1000 centigrade. I then cool it rapidly. I then reheat the body to substantially the same temperature before mentioned and finally cause or allow it to cool slowly. By this process I attain the desirable result before mentioned. I

Cooling rapidly, as herein referred to, means cooling at such a rate as that the changes effected by raising the material to the definite temperature stated are retained substantially unaltered.

Cooling slowly, as herein referred to, means cooling at such a rate as to permit the slow rearrangement of the molecules with reference to one another so that the condition of strain or hardness is removed and .the materlal becomes soft, often accompanied by a more uniform distribution of the elements throughout the mass.

I claim 1. The herein described process of reducing the total magnetic and electric loss inl an iron silicon, aluminium, manganese alloy,.

which consists in first heating said alloy to a high temperature, below its melting point, then cooling sail alloy rapidly, then re heating said alloy to substantially the same high temprature as before, and then cooling said alloy slowly.

2. The process of reducing the total magnetic and electric loss in an alloy containing iron and silicon, which consists in heating alloy to a relatively high temperature below its -melting point, then cooling the alloy rapidly so that the changes effected by heating the: material to the hi h temperature stated are retained substantlally unaltered,

then reheating said alloy to substantially the same temperature as before and then cooling said alloy slowly.

In testimony whereof I have signed my name hereto in the presence of two witnesses. ROBERT ABBOTT HADFIELD. Witnesses:

WILLIAM CRoss, JOHN WM. CRAWLEY. 

